Location specific event broadcasting

ABSTRACT

Applications in a broadcast environment distribute events in real-time to a large number of receivers within specified geographic locations while efficiently sharing bandwidth resources with other applications using the same broadcast network. Applications need not be aware of the other applications sharing the resources, nor of the methods, protocols, and other mechanisms used to actually broadcast the data over the broadcast medium. Server-side applications that serve data, send notifications, or distribute events to specific locations within the network use a broadcast location manager. Client applications that receive such data, notifications, or events use a client location filter to obtain events that are relevant based on the location of the device. The broadcast location manager and client location filter work together to reliably and efficiently transmit data, notifications, and events to specific locations over the broadcast network for all applications involved.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/022,914, entitled “Location Specific Event Broadcasting,” filed Jan.30, 2008, which application is a continuation-in-part of U.S. patentapplication Ser. No. 11/626,707, entitled “Reliable Event Broadcasterwith Multiplexing and Bandwidth Control Functions,” filed on Jan. 24,2007, which claims the benefit of the following United States patentapplications: (1) U.S. provisional patent application No. 60/763,385,entitled “Reliable Event Stream Distributor,” filed Jan. 31, 2006; (2)U.S. provisional patent application No. 60/816,322, entitled “ReliableEvent Broadcaster,” filed Jun. 26, 2006; and (3) U.S. provisional patentapplication No. 60/868,868, entitled “Reliable Event Broadcaster WithMultiplexing And Bandwidth Control Functions,” filed Dec. 6, 2006, thecontents of which are hereby incorporated in their entirety byreference.

TECHNICAL FIELD

This invention relates to the distribution of events, notifications, andother data to applications running on client devices in a broadcastnetwork environment. More specifically, this invention relates to theefficient usage of the broadcast medium to support location directeddistribution of data from serving applications to receiving applicationssharing the same broadcast resources.

BACKGROUND

The increasing adoption of data services by users has resulted in arelated increase in the types of such services available, and in thevariety of data and applications of interest to those users. Users ofmobile wireless devices may receive sports information, news, stockquotes, and real-time data specific to a particular applicationexecuting on their device, as well as emergency notifications andlocation specific data.

However, the use of mobile wireless devices such as mobile phones, PDAs,and wirelessly connected laptop computers introduces certain factorsinto any system designed to deliver data to applications executing onthose devices, where some of the factors may not be significant orrelevant in a fixed high-speed bidirectional communications system (suchas an Internet based communications system). For example, a situation inwhich a mobile device must communicate with a central data store orserver over a wireless network may introduce bandwidth constraints,latency concerns, intermittent connectivity problems, and prohibitivecost into any system designed to transfer data and content to a user ofa client device. In addition, the lower available bandwidth as comparedto a high-speed wire line network may place constraints on the type orcomplexity of the data or content that can be effectively delivered.Also, mobile networks typically can not handle a large number ofsimultaneous client-initiated unicast (i.e., individually addressedserver to client communications) transactions without severe adverseimpact on other network traffic. Similarly, latency and intermittentconnectivity concerns may impact the ability of the client device tocommunicate with a source of data or content to confirm delivery ofcontent. In addition, mobile and other specialized devices typicallyhave characteristics that impose constraints on the storage andprocessing of data that are not present when using desktop computers orother devices connected to a high speed bidirectional network. Theseconstraints may include display size and resolution, data processingspeed, and data storage capacity.

As a result, a threshold issue in determining how best to deliver datato a device is that of the mode of data transfer used for communicationsbetween intended recipients and the network infrastructure. In manytypes of networks, communications between the network infrastructure andindividual users may be accomplished by either a point-to-pointcommunication or by the broadcast of data to a group of recipients. Eachmethod of data transfer has certain advantages and associateddisadvantages, both with regards to optimal network infrastructure usageand with regards to enabling effective use of the type of data beingtransferred.

For example, point-to-point communications are most efficient for arelatively small group of recipients, as they may require significantinfrastructure overhead in terms of recipient device addressing,allocation of dedicated bandwidth, and management of requests fromdevices and the related processing of responses to those requests.Another disadvantage of point-to-point communications is that the costin terms of network resources and overhead is proportional to the numberof client devices receiving the transmission, so that costs generallyscale directly with the number of recipients.

In contrast, broadcasting data to a larger group of recipients may bemore cost-effective and a better way to allocate network infrastructureresources in certain situations and with regards to certain types ofdata. Broadcasting provides benefits in terms of efficiency andscalability, and the cost for broadcasting data is not directlyproportional to the number of recipients. Broadcasting enables data tobe delivered efficiently to a larger group of recipients without theneed for communicating client-side requests to a server and may be moreefficient in terms of resource usage for certain types of applications.Broadcasting is capable of providing comparatively lower cost per bit ofdata transferred, and for certain applications may be a more practicaland effective means of delivering data to interested users.

The type of data or application for which the data is intended may alsointroduce factors that should be considered in deciding upon the desiredmode of data transfer. Certain types of applications requireasynchronous, simultaneous distribution of data to a large set ofclients. These applications include, but are not limited to, safetyalerts, emergency notifications, traffic and extreme weather updates,sporting event updates, news updates, stock quote updates, or other datathat is of potential interest to a large group of users and is timesensitive or whose value dissipates rapidly. For such applications, itmay be more important to provide the relevant data to a region orsection of a network's coverage than to respond to only those users whospecifically request the data. In addition, in situations ofintermittent or unreliable coverage, the time and network resourcesrequired for processing a request-response interaction may not beavailable when needed.

For these and other reasons, and particularly for bandwidth-constraineddata distribution networks such as many mobile data networks, it isoften advantageous to utilize a broadcast mode for distribution ofevents or data. Note that as used herein, the term “events” or “data”refers to data of arbitrary size and type that is meaningful or relevantto the application receiving the data. Examples include a messageintended to be displayed to the user of the receiving application, datato be presented within an application (e.g., news, weather, sportsinformation or updates), a video clip to be played to the user, or adata update for the application.

In many cases, events are broadcast to client devices located in aspecific region. One method used for location-based delivery broadcastsall events to all locations. The client filters the received events sothat the client only processes those events that are targeted to itslocation. The disadvantage to this solution is that bandwidth togeographic locations where the event is not relevant is wasted since noclient in the location will use the event.

Another method used for location-based delivery where applications sharethe same network resources dedicates bandwidth channels to eachapplication based on the locations where the application plans to sendevents. The application is guaranteed to have that bandwidth availablefor delivery of events to each of those locations. However, dedicatingchannels to each application can be an inefficient use of the totalbandwidth. Since most non-streaming applications do not constantly usethe bandwidth, there are frequently times where bandwidth goes unused.For example, a sports application sends data only when an event occursduring the sporting event. Even if such events occur once a second, theamount of data sent is so small that a dedicated channel would be unusedmost of the time.

What are desired are a system and method for efficiently using abroadcast mode of data transfer to manage the location-specificdistribution of data to a variety of applications executing on multipleclient devices operating in a network, where such system and methodovercome the noted disadvantages of existing approaches.

SUMMARY OF THE INVENTION

The present invention permits applications in a broadcast environment todistribute events, notifications and other data reliably in real-time toa large number of receivers within specified geographic locations whileefficiently sharing bandwidth resources with other applications usingthe same broadcast network. Applications need not be aware of the otherapplications sharing the resources, nor of the methods, protocols, andother mechanisms used to actually broadcast the data over the broadcastmedium. An application is guaranteed a minimal level of service for eachlocation it wishes to broadcast to, while network operators retaincontrol over the usage of the resources. Server-side applications thatserve data, send notifications, or distribute events to specificlocations within the network use a broadcast location manager. Clientapplications that receive such data, notifications, or events use aclient location filter to obtain events that are relevant based on thelocation of the device. The broadcast location manager and clientlocation filter work together to reliably and efficiently transmit data,notifications, and events to specific locations over the broadcastnetwork for all applications involved.

In some embodiments, the present invention is directed to a method forfiltering events. A plurality of events are received at a client device.At least one event is associated with a location tag that identifies aphysical location in a network. The physical location is smaller than anarea served by the network. The location of the client device isdetermined. The event is forwarded to an application in the clientdevice if the location of the client device is within the physicallocation identified by the location tag.

In some embodiments, the present invention is directed to a method forbroadcasting events to fine-grained locations in a network. A physicallocation is identified in a network. The physical location is smallerthan an area served by the network. The physical location is mapped to anetwork address. A fine-grained location is identified within thephysical location. An event is to be distributed to client deviceswithin the fine-grained location. Events to be distributed to thefine-grained location are tagged with a location restriction. The eventsare broadcast to the physical location. The events are filtered based onthe location restriction such that only client devices located withinthe fine-grained location process the events.

In some embodiments, the present invention is directed to a system forbroadcasting events to fine-grained locations in a network. The systemincludes a broadcast location manager installed on a server and a clientlocation filter installed on a client device and coupled to thebroadcast location manager by a broadcast distribution network. Thebroadcast location manager includes a policy manager, a topologymanager, an intake manager and a broadcast manager. The policy managerdefines a physical location in a network to which events are broadcast.The physical location is smaller than an area served by the network. Thepolicy manager also defines a fine-grained location within the physicallocation. An event is to be distributed to client devices within thefine-grained location. The topology manager generates a client topologytable which includes a mapping of location tags to physical locations inthe network. Each physical location is identified by a network address.The intake manager provides an event to be distributed to thefine-grained location with a location tag. The broadcast managerbroadcasts events to the physical location. The client location filterincludes a client topology table manager and an event filter. The clienttopology table manager receives the client topology table from thetopology manager. The event filter determines whether the client deviceis located in the fine-grained location based on the location tag andthe client topology table. The event is forwarded to the correspondingapplication in the client device when the client device is located inthe fine-grained area of the network.

In some embodiments, the present invention is directed to a method forbroadcasting events to locations in a network. The method includesidentifying a physical location in a network. The physical location issmaller than an area served by the network. The physical location ismapped to a plurality of network addresses. Events are broadcast toclient devices in the physical location via a broadcast distributionnetwork.

These and other advantages of the invention will be apparent to those ofordinary skill in the art by reference to the following detaileddescription and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of a system for broadcasting datato specific locations of a wireless network;

FIG. 2 is a functional block diagram of a broadcast location manager;

FIG. 3 is a functional block diagram of a topology manager;

FIG. 4 is a functional block diagram of a client location filter;

FIG. 5 is a flow diagram illustrating a method of executing an eventfilter algorithm;

FIG. 6 is a flow diagram illustrating a method of performing eventfiltering when a current version of the client topology table is notlocally stored on a client device; and

FIG. 7 is a functional block diagram of a broadcast location managerillustrating bandwidth allocation for a location-based broadcast server.

DETAILED DESCRIPTION OF THE INVENTION

Although in portions of the following description the present inventionwill be discussed with reference to mobile wireless devices operating ina wireless network, it is to be understood that that the inventivesystems, apparatus and methods are generally applicable to other typesof devices as well, and to networks other than wireless networks (e.g.,fixed high-speed bidirectional networks such as an Internet basedcommunications networks, or fixed or wireless bidirectional networks inwhich communication in one direction is faster than in the other).Applicable devices include, for example, ATM machines, informationalkiosks, vending machines, and navigation systems. One example of asituation in which the present invention would be applicable would be anautomobile navigation system where there is no or only limited abilityfor the user device to communicate with the source of the data. Anotherexample is that of an information kiosk that may have limited upstreamcommunications capabilities. In general, the present invention is mostapplicable to client devices where there is a broadcast mechanism orother efficient data distribution mechanism in one direction (network tomany devices), but there is not an efficient/cost-effective or availabletwo-way mechanism to pull data customized for each device. Although theinvention provides significant benefits for such networks, as mentioned,in general it may be used in the context of high-speed fixed or wirelessbidirectional networks with symmetric or asymmetric communicationscapabilities.

DEFINITIONS

Unless defined otherwise, all technical and scientific terms used hereinhave the meaning commonly understood by a person skilled in the art towhich this invention belongs. As used herein, the following terms havethe meanings ascribed to them unless specified otherwise.

Carousel. A carousel is a collection of events that are continuallybroadcast. When the last event in the carousel is broadcast, broadcastcontinues with the first event in the carousel. Events may be placed on,or removed from the carousel at any time. Each application usingbroadcast services is given one or more carousels. Using multiplecarousels enables applications to prioritize different classes of eventsit broadcasts. Events on a carousel do not necessarily need to bedelivered in a set order, such as first in first out. Items on acarousel may be broadcast in any arbitrary order either by moving orplacing events at the front of the queue, or tagging events using sometype of priority system that determines which event will be the next tobe broadcast.

Location-based Carousel. A location-based carousel is a carousel that isconfigured to broadcast events to a particular network location.

Broadcast Location Manager. The broadcast location manager provides amechanism for applications to direct broadcast events to specificgeographic locations over a shared network resource. Applications neednot be aware of the other applications sharing the broadcast resources,nor of the methods, protocols, addressing schemes and other mechanismsused to actually broadcast the data over the broadcast medium.

Client Location Filter. The client location filter checkslocation-directed events it receives and using the location table,determines whether the event is targeted for the device based on itscurrent location. If not, the event is discarded.

Event. An event is a piece of data of arbitrary size and type that ismeaningful to the application receiving the event. Events can be files,notifications, alerts, media clips, or other data objects. Events may besent one after another or only occasionally, depending on theapplication.

Session. A session is setup whenever an application has events todistribute. Application clients subscribe to sessions to receive events.Sessions have certain characteristics that determine how events usingthe channel get broadcast. Example characteristics include parameterssuch as latency, reliability, linger time and location specificinformation. The location information specifies where events are to bebroadcast.

Broadcast Topology Table. The broadcast topology table, provided by thebroadcast network operator, defines the physical geographic locationsthat can be broadcast to and how to address them.

Service Topology Table. The service topology table defines a set ofcommon locations that any application can use to specify wherelocation-based events can be broadcast. The service topology tablecontains a list of logical location names, and information for mappingthose locations to specific network addresses as defined by thebroadcast topology table. There need not be a one-to-one correspondencebetween logical locations names and broadcast topology locations. Theservice topology table also optionally includes client-based locationinformation for each location defined. This information defines how aclient determines whether or not it is currently located in the definedlocation based on local location information available to the device.The client-based information is used to generate client topology tablesto be distributed to clients on the network.

Client Topology Table. The client topology table is used at the clientdevice to determine whether an event should be accepted based on theevent's location tag and the device's current location. Locations in thetable can be specified in any number of ways, such as GPS polygons, zipcodes, or broadcast tower IDs. The table is managed by the server andbroadcast to all client devices.

Event Location Tag. An event can be tagged with the location specifyingwhere the event is valid. When present, the client location filter usesthe event location tag to determine whether or not the event should beaccepted.

Network Location. A network location is an actual geographic locationthat the underlying broadcast network supports broadcast to. Acollection of network locations are defined in the broadcast topologytable.

Location. A location is defined by the service provider for use byapplications. This allows applications to address location-specificevents using the same location names regardless of the physical networkbeing used. Locations can be subsets of network locations, a full orpartial combination of one or more network locations, or a disjointunion of either of the above.

Implicit Application Group. An implicit application group is a group ofapplications that are allowed to broadcast events to the same location.The group is implicitly defined because the applications can broadcastevents to the same location.

Explicit Application Group. An explicit application group is anexplicitly defined group of applications that share the aggregatebandwidth of a common subchannel.

Subchannel. A subchannel is a full or partial broadcast resource. Thebroadcast operator typically gives a service provider a particularbandwidth resource over their network. The service provider can dividethe bandwidth resource into one or more subchannels, and define groupsof applications that can use each defined subchannel. Each subchannelhas a defined aggregate bandwidth.

Physical Channel. A physical channel is a location-specific broadcastchannel defined by the broadcast network provider.

Location Restriction. A location restriction describes a subset oflocation. For example, a location restriction for New York State wouldbe New York City. The subset need not necessarily be geographicallycontiguous. For example, Central Park and Bronx Zoo could be defined asa location restriction for New York City. Multiple location restrictionsmay be defined for a single location to handle devices which identifytheir locations using different methodologies. For example, there may bea location restriction defined using GPS polygons, and another locationrestriction defined using zip codes.

The present invention permits applications in a broadcast environment todistribute events, notifications and other data reliably in real-time toa large number of receivers within specified geographic locations whileefficiently sharing bandwidth resources with other applications usingthe same broadcast network. Applications need not be aware of the otherapplications sharing the resources, nor of the methods, protocols, andother mechanisms used to actually broadcast the data over the broadcastmedium. An application is guaranteed a minimal level of service for eachlocation it wishes to broadcast to, while network operators retaincontrol over the usage of the resources. Server-side applications thatserve data, send notifications, or distribute events to specificlocations within the network use a broadcast location manager. Clientapplications that receive such data, notifications, or events use aclient location filter to obtain events that are relevant based on thelocation of the client device.

The broadcast location manager and client location filter work togetherto allow multiple applications to reliably and efficiently transmitdata, notifications, and events to specific locations over a commonbroadcast network. The broadcast location manager gives server-sideapplications the ability to publish events that can be directed tospecific geographic locations over the broadcast network. The broadcastlocation manager translates locations specified by applications intonetwork specific instructions for delivery to the appropriate part ofthe broadcast network. Applications may send events to locations thatare more specific than the underlying network allows. In such cases, thebroadcast location manager broadcasts the events to the smallestgeographic area that covers the location where the application wishes tobroadcast.

Client-side applications can further filter events based on morespecific, locally known location information using the client locationfilter such that clients in those locations where the event is nottargeted ignore the event. The client location filter running on each ofthe client devices uses information provided by the broadcast locationmanager to perform the location-based filtering.

Applications may define and send events to locations that not only are asubset of a location supported by the underlying network, but mayoverlap one or more subsets of those locations. The broadcast locationmanager in conjunction with the client location filter may efficientlyroute the events to those locations.

Broadcast applications cooperate to share bandwidth resources. Theapplications may often transmit data at the same time, or may not adhereto the bandwidth limitations assigned to them. Applications do notnecessarily know about how other applications are using the samebroadcast resources. This is especially true for location-based eventdelivery. Different parts of the network may experience different loadsdepending on where events are being delivered. The broadcast locationmanager manages event delivery by maximizing the number of applicationsthat can be deployed by the network operator.

The broadcast location manager provides the aforementioned functions viaseveral components and a number of reliable event broadcaster moduleplug-ins. The components include a topology manager that providesbroadcast network operators, service providers, and applicationdevelopers a means to efficiently manage and address locations withinthe physical broadcast network. Location-based plug-ins are provided fora reliable event broadcaster's policy manager, session manager, intakemanager, event scheduler, and broadcast manager.

The policy manager provides service providers the ability to enable orrestrict where applications can broadcast events, and the bandwidthresources allocated to each application for each location it canbroadcast to. The session manager gives applications the ability todefine one or more locations where an application session's events willbe broadcast, then creates a location-based event carousel for eachlocation for delivery of those events. The intake manager tags eventswith location information in cases where the event may be received bydevices in the network that are outside the desired broadcast location.The event scheduler manages the relative rate at which events formultiple applications destined for the same location are broadcast. Thebroadcast manager obtains events from the various location-basedcarousels based on the policies set forth by the event scheduler. Thebroadcast manager then broadcasts the events over the network using thebroadcast network topology rules defined by the broadcast networkprovider such that multiple location-based carousels are optimized forapplications sending events.

The client location filter utilizes event reception and distributionmodules of a broadcast client toolkit to filter events received based onlocation tags that may be included with the events. The client locationfilter includes a client topology table manager and an event filter. Theclient topology table manager obtains, either by monitoring a broadcast,or explicitly requesting, client topology tables. The event filter usesevent location tags along with the client topology table and the clientdevice's current location to determine if events that are received areto be forwarded to broadcast client toolkit distribution manager, whichis responsible for distributing events to applications running on thedevice.

FIG. 1 is a functional block diagram of a system for broadcasting datato specific locations of a network. The system includes a broadcastdistribution network 100 (e.g., a wireless operator or carrier'snetwork) and a server-side broadcast location manager 200. The broadcastdistribution network 100 may serve multiple wireless networks, such asnetwork 1 and network 2. Network 1 includes a first broadcast tower 110and a second broadcast tower 120 that serve client devices 130, 140, 150located within network 1. Network 2 includes a third broadcast tower 160that serves client devices 170, 180 located within network 2. As shownin the figure with reference to client device 130, each client deviceincludes a client location filter 400.

In general, the broadcast location manager 200 delivers events to thebroadcast distribution network 100 such that the events may be deliveredto specific physical locations in network 1 and network 2. The clientlocation filter 400 in the client device 130 receives the data anddiscards the events that are not marked for delivery to the locationwhere the client device 130 currently resides. Thus, the events that aremarked for delivery to the location where the client device 130currently resides are provided to the applications on the client device130 that subscribed to receive the events.

In more detail, broadcast applications (App 1 and App 2) each distributeevents that are tagged with a specific network location or set oflocations. For example, App 1 distributes events 1, 2 and 3, and App 2distributes events 4, 5 and 6. The events are provided to the broadcastlocation manager 200. As described in detail below, the broadcastlocation manager 200 determines which physical network locations, i.e.,IP address(es), should receive the event based on location tagsassociated with each event.

For example, event 1 includes a tag that corresponds to a physicallocation in network 1 (e.g., the entire state of New York). Todistribute event 1 to the mobile devices in the location correspondingto the location tag, event 1 is provided to both the first and secondbroadcast towers 110, 120. Similarly, event 6 is associated with a morefine-grained location (e.g., Long Island) and, therefore, is provided toonly one broadcast tower that serves that location (e.g., the firstbroadcast tower 110).

As shown in FIG. 1, the client device 130 receives events 1, 4 and 5from the broadcast distribution network 100 via the second broadcasttower 120. The location tag associated with event 4 identifies a regionin network 1 that does not include the entire range of physicallocations served by network 1. For example, the physical locationassociated with event 4 may be limited to the western portion of NewYork State. The client device 130 may be located outside the regionassociated with event 4 (e.g., the device is actually in New York City).In this case, the client device 130 determines that its location is notin the same region identified by the location tag in event 4. Thus, theclient location filter 400 discards event 4 such that the client device130 only processes the events that correspond to the current location ofclient device 130 (e.g., events 1 and 5).

FIG. 2 is a functional block diagram illustrating an embodiment of thebroadcast location manager 200. The broadcast location manager 200includes a policy manager, a session manager 240, an event scheduler250, an intake manager 270, a broadcast manager 280, a topology manager300 and location-specific application carousels 700. Each component ofthe broadcast location manager 200 is described in detail below. Theoverall functionality of the broadcast location manager 200 is describedfirst.

The broadcast network operator 210 specifies the granularity of howgeographic locations can be addressed. The granularity may range frombeing able to address each broadcast tower in a network, to only beingable to specify one or two regions in a country. The broadcast networkoperator 210 provides the broadcast location manager 200 with broadcasttopology details. For example, the broadcast network operator 210defines the network locations and how to address them. The broadcastlocation manager 200 uses the broadcast topology details to broadcastevents to specific locations in the network based on applicationrequests.

The broadcast location manager 200 may simultaneously manage multiplenetworks (e.g., BCMCS, DVB-H, and MediaFLO). Each network is associatedwith its own broadcast topology table. The application does not requirespecific details of any network, and can broadcast events over any orall networks using the same interface. The broadcast location manager200 handles the translation from application-specified locations to thephysical addressing needed for broadcast to that location on eachnetwork expressed as, for example, a multicast IP address and port.

The broadcast network operator 210 may define network locations in avariety of ways. For example, network locations may be defined by GPSpolygons, zip codes, broadcast tower IDs, or city, state, and countrynames. The broadcast location manager 200 is configured to understandeach addressing scheme and to translate requests made by an applicationinto any of the addressing schemes.

An example of a broadcast topology table is shown below:

Network Location Local Interface/ Location Description SpecificationNetwork Range US United States (GPS Polygon, (IP addresses/ Zip Codes,etc.) address range/ports) NYS New York State (GPS, zip, etc.)(addresses/range) NJS New Jersey State (GPS, zip, etc.)(addresses/range) CTS Connecticut State (GPS, zip, etc.)(addresses/range) NYC New York City (GPS, zip, etc.) (addresses/range)

A service provider may utilize the policy manager 220 to createapplication-specific selection policies 230 that include location-basedinformation. The location-based information may include restrictions onwhich locations the application may broadcast to, and the bandwidthresources the application is allowed to use for each location to whichit may broadcast. For example, a service provider may define thefollowing broadcast topology for the United States which is divided upinto five regions:

Network Location Aggregate Bandwidth Northeast 100 Kb/sec  Southeast 75Kb/sec Midwest 75 Kb/sec Southwest 50 Kb/sec West 100 Kb/sec 

The service provider may provision applications and restrict thelocations each application can broadcast to, for example:

Application Priority Locations Allowed Stock Ticker Medium Northeast,West Baseball Medium Southeast, Midwest, West National News Low All SkiReport Low Northeast, Midwest, West Hurricane Alert High Southeast,Northeast

All applications that may broadcast to the same location form animplicit group. An implicit group may be subject to applicationbandwidth constraints as described in U.S. patent application Ser. No.11/626,707, filed on Jan. 24, 2007, and entitled “Reliable EventBroadcaster with Multiplexing and Bandwidth Control”. Specifically, thesum of the minimum guaranteed bandwidths for all applications in thegroup may not exceed the aggregate bandwidth available to that physicallocation. Additionally, for each priority level defined, the sum of theminimum expected bandwidth for all applications at a particular prioritylevel plus the sum of the minimum guaranteed bandwidths for allapplications with a lower priority level may not exceed the aggregatebandwidth available to that physical location. The minimum expectedbandwidth may be preempted by higher priority sessions when the higherpriority sessions become active.

For the examples given above, the following implicit application groupsare defined:

Location Bandwidth Implicit Application Group Northeast 100 Kb/sec Stock Ticker, National News, Ski Report, Hurricane Alert Southeast 75Kb/sec Baseball, National News, Hurricane Alert Midwest 75 Kb/secBaseball, National News, Ski Report Southwest 50 Kb/sec National NewsWest 100 Kb/sec  Stock Ticker, Baseball, National News, Ski Report

The service provider may choose to define separate bandwidth policiesfor each location an application can broadcast to, or define a singlebandwidth policy that applies to all locations that an application canbroadcast to. In either case, the policy manager 220 ensures that thebandwidth policies defined for applications that may broadcast to thesame location adhere to the bandwidth definition restrictions.

In the following example, one application is allocated the samebandwidth resources for all regions it can broadcast to, whereas anotherapplication is given separate resource allocations for each region itcan broadcast to.

Bandwidth Minimums Application Priority Guaranteed Expected HurricaneAlert High 50 Kb/s 50 Kb/s National News: Low Northeast 10 Kb/s 25 Kb/sSoutheast 10 Kb/s 10 Kb/s Midwest 20 Kb/s 25 Kb/s Southwest 25 Kb/s 40Kb/s West 15 Kb/s 25 Kb/s

The service provider may further refine how applications that maybroadcast to the same location share bandwidth resources by defining oneor more explicit application groups for a particular location. In thiscase, each application group is allocated a portion of the totalbandwidth available to the service provider for that location. Thoseapplications are then subject to constraints based on the allocatedbandwidth.

The following table shows an example of explicit application groupsdefined for the Northeast region:

Location Bandwidth Explicit Application Group Northeast - Group 1 60Kb/sec Stock Ticker, National News Northeast - Group 2 40 Kb/sec SkiReport, Hurricane Alert

As mentioned above, the policy manager 220 provides service providersthe ability to define and manage location-based application policies.This includes defining restrictions as to which locations a particularapplication can broadcast events to, defining explicit applicationgroups for particular locations, and defining the bandwidth limits foreach application. Additionally, the policy manager 220 enforces thebandwidth restrictions for each implicit and explicit application group.These restrictions are enforced by applying the application bandwidthconstraints for each implicitly and explicitly defined group. If anygroup fails, the applications in that group are marked and the serviceprovider is required to modify the bandwidth allocations for one or moreof those applications to satisfy the application bandwidth constraints.

When an application creates a session to broadcast events, theapplication can specify one or more locations where the events broadcastget delivered. By default, the locations are inherited from theapplication policy. However, the application may specify a subset of thelocations defined in the application policy. The application may alsospecify locations that are more fine-grained than what are provided inthe application policy. For example, if the application policy specifiesthat an application can broadcast events to the Northeast region of theUnited States, the application may specify, when opening alocation-based event session, that it wants to broadcast only to thestate of New York. The application can specify a sub-region using a GPSpolygon, zip or postal codes, tower identifiers, or any other meansallowed by the service provider. The service provider may define a setof more fine-grained locations which define sub-regions regularly usedby the application. This feature will be discussed in further detailbelow.

When verifying that an application's session bandwidth constraints areadhered to, the session manager 240 takes into account the locationseach opened session broadcasts to. Locations that do not overlap aregrouped separately and need not be counted against each other. In thefollowing example, a national news application broadcasts to fiveregions of the United States:

Bandwidth Requests Session Name Location Guaranteed Expected NationalHeadlines All 1 Kb/s  5 Kb/s Coastal News Northeast, Southeast, 1 Kb/s 5 Kb/s West Farm Report Midwest, West 2 Kb/s 10 Kb/s Northeast ReportNortheast 2 Kb/s 15 Kb/s

Based on the application location-based session requests shown above: 1)the following groups are formed; 2) the application session bandwidthrequests are summed; and 3) the results are checked against theapplication policy to determine if the requests can be satisfied:

Effective Bandwidth Requests Location Session Names Guaranteed ExpectedNortheast National Headlines, Coastal 4 Kb/s 25 Kb/s News, NortheastReport Southeast National Headlines, Coastal 2 Kb/s 10 Kb/s News MidwestNational Headlines, Farm Report 3 Kb/s 15 Kb/s Southwest NationalHeadlines 1 Kb/s  5 Kb/s West National Headlines, Coastal 4 Kb/s 20 Kb/sNews, Farm Report

When grouping by location, the locations are the network locations thatthe broadcast topology allows, not necessarily the locations theapplication specified when it opened the session. The following tableapplies to a national news application.

Bandwidth Requests Session Name Location Guaranteed Expected NationalHeadlines All 1 Kb/s 5 Kb/s Coastal News Northeast, Southeast, 1 Kb/s 5Kb/s West Farm Report Midwest, West 2 Kb/s 10 Kb/s  Northeast ReportNortheast 2 Kb/s 15 Kb/s  New York Headlines GPS polygon for New 1 Kb/s10 Kb/s  York State New Jersey Headlines GPS polygon for New 1 Kb/s 5Kb/s Jersey State California Headlines GPS polygon for 1 Kb/s 5 Kb/sCalifornia State

Even though New Jersey and New York do not overlap geographically, basedon the broadcast topology granularity, sessions opened to either stateare broadcast to, and, therefore, are counted against the Northeastregion. Similarly, the session opened to California is counted againstthe West region. The following grouping and effective bandwidth requestsresults:

Effective Bandwidth Requests Location Session Names GuaranteedPreemptable Northeast National Headlines, Coastal 6 Kb/s 40 Kb/s News,Northeast Report, New York Headlines, New Jersey Headlines SoutheastNational Headlines, Coastal 2 Kb/s 10 Kb/s News Midwest NationalHeadlines, Farm Report 3 Kb/s 15 Kb/s Southwest National Headlines 1Kb/s  5 Kb/s West National Headlines, Coastal 5 Kb/s 25 Kb/s News, FarmReport, California Headlines

The session manager 240 provides applications with the ability to defineand manage location-based sessions and enforces the session bandwidthconstraints for each network location that an application can broadcastto. The session manager 240 determines if an application'slocation-based session request adheres to the constraints set up in theapplication's policy by grouping all sessions the application has openbased on network locations that overlap. A session bandwidth constraintis applied for each group. If any group fails, the new session requestcan not be satisfied.

The session manager 240 also provides application feedback regarding thequality of service each location is experiencing. Each separate networklocation may experience a different quality of service, since bandwidthmanagement and optimization is applied to each network locationseparately. This is required because the dynamic mix of traffic isdifferent for each location.

When an application creates a session to broadcast events to aparticular location within the network, one or more location-specificapplication carousels 700 are established to support delivering eventsto those destinations. The number and destinations of the carouselsdepend on the application's requirements and the broadcast topologytable. One carousel is created for each network destination to which theserver has determined events within that session are to be sent. In thefollowing national news application example, three network locations areto be broadcast to: Northeast, Midwest, and West.

Bandwidth Requests Session Name Locations Guaranteed Expected Big CityTechnology New York City, 2 Kb/s 10 Kb/s Headlines Boston, Chicago, SanFrancisco, Seattle

The Northeast covers New York City and Boston, the Midwest coversChicago, and the West covers San Francisco and Seattle. Threelocation-based carousels are then created. Each carousel may be given adifferent allocated bandwidth and, therefore, experience a difference indata broadcast quality of service, depending on other applicationsessions using the same location-based broadcast resource.

By default, events for a particular application session are broadcast tothe location or locations specified when the session is opened. However,applications may override the default by specifying a subset oflocations to where particular event is broadcast. In such cases, theevent is placed on the appropriate carousel or carousels for broadcastto the network location.

A event scheduler 250 determines the order and rate at which events arebroadcast to each network location in the broadcast network by using theapplication-specific selection policies 230, session policies 260, andcurrent carousel states to optimally allocate bandwidth for each networkdestination in the entire system. The event scheduler 250 allocatesbandwidth using the location-based bandwidth allocation proceduredescribed below.

The event scheduler 250 allocates bandwidth to the location-basedapplication sessions. All application sessions that broadcast to thesame network location are grouped together, and the aggregate bandwidthavailable to that location is divided amongst the sessions in the group.The division is accomplished using the bandwidth allocation procedure inwhich carousels are grouped by network destination, as described withreference to FIG. 7. Bandwidth is then allocated to the group based onthe aggregate bandwidth available to that physical destination.

The intake manager 270 tags events with location information, and sendsthe events to the event scheduler 250 for placement on the appropriatecarousel. The intake manager 270 appends location tags to events thatare not intended to be used by all client devices that may receive theevent. This is particularly useful in situations where the broadcasttopology does not support fine-grained control over where events arebroadcast. As discussed with reference to FIG. 4, the client locationfilter 400 examines the tags to determine whether the client device isin the desired location and, if so, accepts the event.

A single event may have more than one location tag if that event is tobe distributed to multiple locations. If the client location filter 400determines that the client device is in any one of those locations, theclient location filter 400 accepts the event. The intake manager 270 mayoptimize event tagging when more than one location is specified by theapplication. Location tags that may never correspond to parts of thenetwork to which an event is transmitted may be stripped from thatevent.

Location tags may also specify locations where an event is not to bereceived. In that case, the client location filter 400 discards theevent if the client device is located within the area described by theevent location tag. The intake manager 270 may optimize the broadcastingof events by not broadcasting events to network locations where theevents may always be discarded by client devices receiving those events.

The broadcast topology table alone is sufficient to enable applicationsto broadcast events to one or more locations. Applications may broadcastto more precise locations than may be defined in the broadcast topologytable by adding a location restriction either to a session or to aspecific event. In cases where an event is to be broadcast to a moreprecise location than the network topology allows, the event is taggedwith the more precise location information. The event is then broadcastto the appropriate physical channels as defined in the network topology.The client location filter 400 examines the location tag to determinewhether or not the client device is intended to receive the event basedon the current location of the client device. Applications can specifydisparate or non-contiguous locations by providing one or more locationrestrictions.

This methodology requires that server-side applications are configuredto specify location restrictions, and client-side filters are configuredto determine whether or not the client devices are located within thelocation restriction. This may be accomplished via GPS polygons, zip orpostal codes, tower identifiers, or any another method supported by thebroadcast network. The broadcast location manager 200 receives locationrestrictions from server-side applications and determines which physicalchannels are to be used to broadcast those events. The client locationfilter 400 uses locally available device location information and thelocation tags included with an event to determine whether or not theclient device is located within the location restriction as specified bythe server-side application.

Each broadcast network may require a different method to specifylocation restrictions. In cases where a server-side applicationbroadcasts events to more than one network, the application may need tospecify location restrictions using multiple formats. The broadcastlocation manager 200 determines the physical channels to use for eachnetwork, and tags each event with the location restriction correspondingto the network on which it is broadcast.

These topology requirements create somewhat of a burden on eachapplication to be aware of how location restrictions are specified foreach broadcast network. The topology manager 300 abstracts the locationrestriction details from each application, and provides logical locationnames that can be used by all applications and are applicable to allbroadcast networks.

FIG. 3 is a functional block diagram of the topology manager 300. Thetopology manager includes a broadcast topology manager 310, a servicetopology manager 320, a client topology extraction module 330, and aclient topology table distributor 340. These modules of the topologymanager 300 allow broadcast network providers and service providers todefine and manage broadcast topology tables 350, service topology tables360, and client topology tables 370.

The broadcast topology manager 310 allows broadcast network operators todefine the network locations using the broadcast topology tables 350.The broadcast topology tables 350 define the network locations that canbe broadcast to and how to address them.

The service topology manager 320 enables service providers to create andmanage the service topology tables 360 to define common locations thatcan be used by all applications regardless of the network broadcast to.Each location is mapped to one or more network locations defined in thebroadcast topology tables 350. The service topology tables 360 contain alist of location names, an optional location tag for use by clientdevices, and information for mapping those locations to specific networkaddresses as defined by the broadcast topology tables 350. The servicetopology tables 360 allow applications to use location names that maymap differently to different broadcast networks. There need not be aone-to-one correspondence between locations names and actual broadcasttopology locations. Locations defined in the service topology tables 360may also be used for defining location-based application policies forgrouping and bandwidth sharing.

A service provider may only require location-specific datacasting at thegranularity of the broadcast topology. In this case, the only meaningfullocations are network locations, or combinations of these locations asdefined in the service topology, and no finer-grained location issupported. No client-based filtering is needed in this case because allclients receiving an event are by definition in the location, so nolocation identifier tags are required in broadcast events. However, thebroadcast server still provides applications with a transparent mappingto networks and addresses, as well as separate bandwidth management foreach network location. Moreover, even in this case, tags may need to beincluded if events can be processed after an interval of mobility by theclient after reception.

A service provider may define finer-grained locations than the broadcasttopology supports. In such cases, the service provider maps thefiner-grained location to one or more network locations that cover morethan the area desired. Since the physical mapping covers an area greaterthan what is desired, a location restriction is specified by the serviceprovider for the location being defined. The location restrictiondefines a geographical subset of the network location defined in thebroadcast topology tables 350. However, since events are broadcast tothe larger network location(s), clients outside the fine-grainedlocation also receive those events. In such cases, the intake manager270 tags events being broadcast to the finer-grained location with thelocation identifier so that client devices in the affected areas canfilter those events.

For broadcast topologies that do not support fine-grainedaddressability, there may be entries in the service topology tables 360that map to the same entry or to multiple entries in the broadcasttopology tables 350. The service topology tables 360 may also includelocation restrictions which may be used by client devices in the networkto determine whether or not they are in the defined location. More thanone location restriction may be defined to support client devices thatdetermine their locations using different methodologies. For example,one location restriction may be defined using GPS polygons, whereasanother location restriction may be defined using zip codes.

Locations defined in the service topology tables 360 need not becontiguous geographically. For example, the service provider may want todefine densely populated areas within one or more states and be able toaddress events to those locations with a single location identifier. Thebroadcast location manager 200 allows service providers to define suchpotentially disparate locations and map them into one or more entries inthe broadcast topology tables 350 along with the restrictions to thoselocations.

An example of a service topology table is shown below.

Location Location Network Name Parent(s) Description RestrictionLocation(s) NYNJ NY, NJ New York and — NY, NJ New Jersey Manhattan NYCManhattan GPS polygon/ NYC zip codes, etc. TriState NY, NJ, CT New YorkCity GPS polygon/ NY, NJ, CT Tri-state Area zip codes, etc. CentralManhattan Central Park GPS polygon/ NYC Park zip codes, etc.

A parent location may refer to one or more locations defined in theservice topology table, or to one or more locations defined in thebroadcast topology table, or one or more entries from both tables. Thetopology manager 300 may create a union of all the restrictions definedin parent entries as well as the location restriction defined for theentry being defined. The union may then be used to determine thephysical channels used to broadcast to the location being defined. Theunion may also be used by a client topology translation module to mapthe newly defined location into client topologies that are used byclient devices to determine whether or not they are located within thatlocation.

Locations may be assigned a location tag, which are added to events thathave a location restriction defined. In the example service topologytable provided above, the logical location NYNJ does not requirelocations tags since the logical location is the union of two physicalchannels, NY and NJ. Events broadcast to both of those physical channelsare intended to be received by all client devices in those locations.Events should be processed in a timely manner. Otherwise, applicationsusing those events may need to be aware of client device movement overtime, or may need to request the client location filter 400 to reexaminethe location tags for an event some time after the event has beenreceived to determine if the event is still applicable to the locationin which the client device is currently residing.

The location “Manhattan” requires the use of location tags. “Manhattan”has a location restriction based on the physical channel NYC, whichdefines the island of Manhattan. Since the physical channel serving thatlocation broadcasts events to all devices in NYC, devices outsideManhattan will receive events destined to that location. In order tohave client devices outside Manhattan (but within NYC) ignore thoseevents, a location tag is added to those events. As described withreference to FIG. 4, the client location filter 400 on each clientdevice filters out events destined for Manhattan on devices that are inNYC, but outside of Manhattan.

The client topology extraction module 330 builds a client topology tablewhich includes a subset of the location restrictions defined for aspecific client device or class of devices. This reduces the size of theclient topology table by removing location restriction information notused by a client device or class of devices. The client topology tablemaps location tags to the client-specific locations. When an event istagged with the location specifying where the event is valid, the clientuses its current location, the client topology table, and the event'slocation tag to determine whether the event should be accepted.

The client locations may be specified using GPS polygons, zip codes,cell tower identifiers, or any other method by which a client devicedetermines its location. Different client devices on the same networkmay identify their locations using different methods. In such cases, theclient topology table may contain several different methods to describelocations. Alternatively, multiple client topology tables may bemaintained and broadcast. The client device is responsible for obtainingthe client topology table with the location descriptions that correspondto its capabilities.

The client topology table is a subset of the service topology table andincludes the name of each defined client-specific location (and/or thelocation tag used to identify that location), and the locationrestriction that may pertain to a particular class of devices. Forexample, if a class of devices determines its location via GPS, fieldsdefining location restrictions using other methods, such as zip codesand tower locations, may not be included.

Client topology tables contain a version number so that the clientdevice may determine whether it has the latest version of the clienttopology table. Events that are tagged also include the client topologytable version number required to correctly filter the event.

The client topology extraction module 330 extracts the fields necessaryfrom the service topology table to create the client topology table.These fields include the broadcast location, the location tag (ifdifferent), and one of more location restrictions for that location,depending on whether a single or multiple client topology tables aremaintained.

The client topology table distributor 340 broadcasts the client topologytables 370 to all client devices in the network. Since client devicesare not always monitoring the network, the client topology tabledistributor 340 rebroadcasts the client topology tables 370 at regularintervals to ensure that client devices entering the network have themost current version.

There may be cases where a client device may not receive the clienttopology table 370 in a timely manner. This may be due to the clientdevice going in and out of coverage at inopportune moments. In suchcases, the client device proactively obtains the client topology tablevia a client-initiated request. In one embodiment, the client topologytable may be obtained by employing a point-to-point data network. Inanother embodiment, the client topology table may be delivered byexisting messaging technologies (e.g., short message service (SMS),multimedia messaging service (MMS), or wireless application protocol(WAP) Push). In a further embodiment, the client topology table may bedelivered by over-the-air provisioning (OTAP) which is used to discoverparameters from local radio network elements. The client topology tabledistributor 340 handles these individual client requests for the clienttopology tables 370. In one embodiment, the number of client devicesmaking such requests is limited so as to avoid flooding the network withpoint-to-point traffic.

The client topology table distributor 340 may optimize distribution ofthe client topology tables 370. A client topology table may become verylarge if a significant number of locations are defined. In such cases,the client topology table distributor 340 may manage multiple tables fordifferent regions, where each table defines locations only within thatregion. The client topology table distributor 340 then broadcasts thesmaller regional table to client devices located within that region.

FIG. 4 is a functional block diagram of a broadcast client toolkit 40that is installed on a client device. The broadcast client toolkit 40includes the client location filter 400, a reassembly manager 440, anevent manager 450, an event cache 460, a distribution manager 470, theapplication-specific selection policies 230, and a session manager 480.The client location filter 400 enhances the location-independent clientprocessing provided by the other components and described in U.S. patentapplication Ser. No. 11/626,707, filed on Jan. 24, 2007, and entitled“Reliable Event Broadcaster with Multiplexing and Bandwidth Control”.Specifically, the reassembly manager 440 assembles larger objects frombroadcast packets, the event manager 450 recognizes new events andprovides notifications to the other components, the event cache 460stores the payloads of received events, the session manager 480 acceptssubscriptions from applications to event sessions, and the distributionmanager 470 distributes received events to the appropriate applicationson the client device, based on application-specific selection policies230.

The client location filter 400 includes a client topology table manager410, locally stored client topology tables 420, and an event filter 430.The client location filter 400 manages the locally stored clienttopology tables 420, and examines incoming events to determine whetheror not to pass them along to applications that are registered to receiveevents from the event source.

The client topology table manager 410 obtains and maintains the clienttopology tables 420 on the client device. The client topology tablemanager 410 monitors a broadcast stream for the client topology tables420. The client topology table manager 410 may monitor continuously, orat predetermined times or intervals. When a new client topology table420 is available and is relevant to the client device, the clienttopology table manager 410 obtains the new table and stores it locally.

The client topology table manager 410 may proactively obtain a clienttopology table. This may be accomplished by directly requesting theclient topology table from the broadcast location manager 200 when theclient location filter 400 determines that it is missing a requiredtable and may not be able to obtain one in a timely manner by monitoringthe broadcast channel containing the client topology tables.

As discussed above, events received at the client location filter 400may be tagged with location information. In such cases, the clientlocation filter 400 determines if the event received is relevant to theclient device's current location. The client location filter 400 makesthe determination using the location tag imbedded in the event, theappropriate client topology table, and the client device's currentlocation within the broadcast network.

The event filter 430 executes an algorithm to determine whether an eventshould be passed to applications (e.g., App 1, App 2, and/or App 3) thatare registered to receive events from the event source. FIG. 5 is a flowdiagram illustrating a method of executing the event filter algorithm.The execution of the algorithm begins when an event is received at theevent filter and a determination is made whether a location tag ispresent in the event (step 500). If the event does not include alocation tag, the fine-grained location of the client device is notrelevant to the event. Thus, the event is forwarded to the applicationsthat subscribe to the event (step 510). If the event includes a locationtag, then the client topology table identifier, the table versionnumber, and the event location are extracted from the tag (step 520).

A determination is made whether the client topology table identifierassociated with the correct table version number is stored locally atthe client device (530). Since the set of locations that are relevant tothe event may be updated periodically, the client topology table may beoutdated if the locations associated with the event have changed but thecorresponding location definitions in the table have not been updated.If the corresponding table is not stored locally, or if the locallystored table is not the correct version, processing proceeds to FIG. 6to determine if the event should be forwarded or discarded (step 540).

If the correct version of the client topology table is stored locally,the location definition that matches the event location is accessed fromthe client topology table (step 550). The type of location definitiondepends on which mechanism the client device uses to determine itslocation (e.g., a radio tower, a GPS receiver, etc.). For example, thelocation definition may be a set of zip codes or a GPS polygon. Sincethere are multiple ways that a client device may determine its location,multiple location definitions may be stored in the client topologytable.

The current location of the client device is obtained (step 560). Adetermination is then made whether the client device's current locationis within the location definition (step 570). If the client device'scurrent location is within the location definition, the event isforwarded to the applications that subscribe to the event for processing(step 510). If the client device's current location is not within thelocation definition (i.e., the client device is in a part of the networkthat is not identified by the location tag), the event is discarded(580).

FIG. 6 is a flow diagram illustrating a method of performing eventfiltering when a current version of the client topology table is notlocally stored on a client device. First, a determination is made toidentify when the next table update will be available from the broadcastchannel that distributes client topology tables (step 600). If theclient topology table will be available within a threshold as set by theservice provider or built-in to the client device (step 605), the clienttopology table manager waits for and downloads the correct version ofthe client topology table (step 610). Processing then proceeds to step625.

If the client topology table will not be available within the thresholdas set by the service provider or built-in to the client device (step605), a determination is made whether the client topology table manageris allowed to proactively obtain the table (step 615). If the clienttopology table manager is allowed to proactively obtain the table, theclient topology table manager explicitly requests and obtains the mostrecent client topology table from the broadcast location manager (step620).

The location definition that matches the event location is accessed fromthe client topology table (step 625). The current location of the clientdevice is obtained (step 630). A determination is then made whether theclient device's current location is within the location definition (step635). If the client device's current location is within the locationdefinition, the event is forwarded to the applications that subscribe tothe event (step 640). If the client device's current location is notwithin the location definition, the event is discarded (645).

If the most recent version of the table is not available locally and cannot be obtained within the threshold amount of time, a determination ismade whether to discard or keep the event (step 650). The determinationmay be made based on one or more of: additional information available inthe location tag; a service provider defined policy, or a policy that isbuilt in to the client device. For example, if a determination can notbe made whether the client device is in the correct location, the policymay determine that: 1) the event is processed; 2) the event isdiscarded; or 3) the event is not processed until the client devicelocation is determined.

The location information attached to an event may be useful to anapplication (e.g., to inform the user of the region to which the eventapplies). Therefore, the distribution manager may make metadatacorresponding to the location information available along with thecontent of the event. The application may communicate with the clienttopology table manager to interpret the location tag.

FIG. 7 is a functional block diagram of a broadcast location managerillustrating bandwidth allocation for a location-based broadcast server.The broadcast location manager 200 includes the event scheduler 240 andthe location-specific application carousels 700. The location-specificapplication carousels 700 include location 1 carousels 700(1), location2 carousels 700(2) and location 3 carousels 700(3). Each locationcarousel 700(1-3) is associated with a set of bandwidth allocationalgorithms 710(1-3) and location data channels 720(1-3).

As shown in the figure, an application publishes one event that may bedistributed to multiple broadcast locations. For example, application Csends the same event to locations 2 and 3, but does not send any eventsto location 1. Thus, the event for application C is provided to thelocation 2 carousel 700(2) and the location 3 carousel 700(3). Likewise,application A provides events to location 1 carousel 700(1) and thelocation 2 carousel 700(2), and application B provides events to allthree location carousels 700(1-3).

Each broadcast location is associated with a particular bandwidth whichmay change depending on the events to be distributed. The bandwidthallocation algorithms 710(1-3) are executed for the correspondinglocation carousels 700(1-3) to optimize the bandwidth for each broadcastlocation. The bandwidth is allocated for each broadcast locationindependently because each data channel 720(1-3) may have a differentcapacity and a different number of events to be distributed from thelocation carousels 700(1-3). By executing the corresponding bandwidthallocation algorithm 710(1-3) for each broadcast location, bandwidth canbe allocated such that an application may receive a better quality ofservice for one location relative to a different location. In otherwords, the allocation of bandwidth may be optimized for each locationrather than tying bandwidth allocation to the worst case scenario.

For example, as shown in the figure, the location 3 data channel 720(3)is the slowest channel. However, the other location data channels 720(1)and 720(2) should not be restricted to the rate at which packets arebeing sent to location 3. In other words, if data packets are sent tolocations 1 and 2 at the same rate at which data packets are sent tolocation 3, bandwidth is unnecessarily wasted for data transmission tolocations 1 and 2. Since bandwidth is allocated for each broadcastlocation independently, a better quality of service is provided toapplications for the packets being sent to locations 1 and 2 relative tolocation 3. By optimizing and multiplexing the bandwidth allocationsseparately, different packets are sent to each broadcast location eventhough each application only publishes one version of an event.

As is apparent from the above description, the present inventionprovides many advantages over conventional data broadcasting techniques.The server and client work together to provide fine-grained control overwhere events can be broadcast and received. Events may be directed tospecific network locations either by server-side only means, client-sideonly means, or cooperative server-side and client-side means. Locationspecific addressing across multiple networks/protocols is abstracted atthe server such that applications have one interface and one set oflocation specifics for all networks and protocols. The broadcasting ofevents is optimized based on the location specified by the application,and the union and/or intersection of addressable locations supported bythe network. The delivery of client topology tables is optimized suchthat a portion of the table may be broadcast based on the broadcastlocation. In other words, parts of the client topology table that willnot be used by the client device are not delivered to the client devicebecause the client device is not present in those locations. Bandwidthresources may be restricted, allocated and shared among groups ofapplications on a location-by-location basis. Location-based carouselsallow a single event broadcast by an application to be delivered tomultiple network locations. The quality of service may be independentlymanaged for each network location where applications are broadcastingevents.

The present invention has been described in terms of specificembodiments. As will be understood by those skilled in the art, theembodiments illustrated above may be modified, altered, and changedwithout departing from the scope of the present invention. The scope ofthe present invention is defined by the appended claims.

1. A system for broadcasting events to fine-grained locations in anetwork, the system comprising: a broadcast location manager installedon a server, the broadcast location manager comprising: a policy managerconfigured to define a physical location in a network to which eventsare broadcast, wherein the physical location is smaller than an areaserved by the network, the policy manager being further configured todefine a fine-grained location within the physical location, wherein anevent is to be distributed to client devices within the fine-grainedlocation, a topology manager configured to generate a client topologytable which includes a mapping of location tags to physical locations inthe network, wherein each physical location is identified by a networkaddress, an intake manager configured to provide an event to bedistributed to the fine-grained location with a location tag, and abroadcast manager configured to broadcast events to the physicallocation; and a client location filter installed on a client device andcoupled to the broadcast location manager by a broadcast distributionnetwork, the client location filter comprising: a client topology tablemanager comprising the client topology table, and an event filterconfigured to determine whether the client device is located in thefine-grained location based on the location tag and the client topologytable, wherein the event is forwarded to the corresponding applicationin the client device when the client device is located in thefine-grained area of the network.
 2. The system of claim 1 wherein thebroadcast location manager further comprises: a session managerconfigured to create a location-specific application carousel for eachphysical location in the network to which events are broadcast.
 3. Thesystem of claim 2 wherein each location-specific application carousel isassociated with an allocated bandwidth.
 4. The system of claim 3 whereinthe broadcast manager is further configured to broadcast the events tothe physical location by optimizing the bandwidth allocated for thelocation-specific application carousels.
 5. The system of claim 1wherein the policy manager is further configured to define a bandwidthallocation policy for each physical location in the network to whichevents are broadcast.
 6. The system of claim 5 wherein the broadcastlocation manager further comprises: an event scheduler configured tomanage the rate at which events are broadcast to the same physicallocation by allocating bandwidth for each physical location based on thecorresponding bandwidth allocation policy.
 7. The system of claim 1wherein the client topology table corresponds to the location of theclient device.
 8. The system of claim 7 wherein the event filter isfurther configured to determine a location change of the client device,the client topology table not corresponding to a current location of theclient device.
 9. The system of claim 8 wherein the client topologymanager is further configured to obtain another client topology tablethat corresponds to the current location of the client device.